From 27d12ea31fcf4d26bb6f0449625fc4679e95646d Mon Sep 17 00:00:00 2001
From: Eric Tang <e_l_tang@outlook.com>
Date: Thu, 5 Jul 2018 12:33:55 -0700
Subject: [PATCH] Remove the debouncing interrupt

---
 right/src/init_peripherals.c   |  3 ---
 right/src/key_debouncer.c      | 32 --------------------------------
 right/src/key_debouncer.h      | 18 ------------------
 right/src/key_states.h         |  3 ++-
 right/src/peripherals/pit.h    |  4 ----
 right/src/usb_report_updater.c | 12 ++++++++----
 shared/key_matrix.h            |  1 +
 7 files changed, 11 insertions(+), 62 deletions(-)
 delete mode 100644 right/src/key_debouncer.c
 delete mode 100644 right/src/key_debouncer.h

diff --git a/right/src/init_peripherals.c b/right/src/init_peripherals.c
index 7efcb20..35f34e2 100644
--- a/right/src/init_peripherals.c
+++ b/right/src/init_peripherals.c
@@ -12,7 +12,6 @@
 #include "init_peripherals.h"
 #include "eeprom.h"
 #include "timer.h"
-#include "key_debouncer.h"
 #include "usb_api.h"
 #include "slave_scheduler.h"
 #include "bootloader/wormhole.h"
@@ -67,7 +66,6 @@ static void initInterruptPriorities(void)
     NVIC_SetPriority(I2C_EEPROM_BUS_IRQ_ID,    0);
     NVIC_SetPriority(PIT_TIMER_IRQ_ID,         3);
     NVIC_SetPriority(PIT_KEY_SCANNER_IRQ_ID,   4);
-    NVIC_SetPriority(PIT_KEY_DEBOUNCER_IRQ_ID, 4);
     NVIC_SetPriority(I2C_MAIN_BUS_IRQ_ID,      4);
     NVIC_SetPriority(USB_IRQ_ID,               4);
 }
@@ -159,6 +157,5 @@ void InitPeripherals(void)
     TestLed_Init();
     LedPwm_Init();
     InitI2cWatchdog();
-    InitKeyDebouncer();
     EEPROM_Init();
 }
diff --git a/right/src/key_debouncer.c b/right/src/key_debouncer.c
deleted file mode 100644
index 0ec19e7..0000000
--- a/right/src/key_debouncer.c
+++ /dev/null
@@ -1,32 +0,0 @@
-#include "key_debouncer.h"
-#include "fsl_pit.h"
-#include "slot.h"
-#include "module.h"
-#include "key_states.h"
-#include "peripherals/test_led.h"
-
-void PIT_KEY_DEBOUNCER_HANDLER(void)
-{
-    TestLed_Toggle();
-    for (uint8_t slotId=0; slotId<SLOT_COUNT; slotId++) {
-        for (uint8_t keyId=0; keyId<MAX_KEY_COUNT_PER_MODULE; keyId++) {
-            uint8_t *debounceCounter = &KeyStates[slotId][keyId].debounceCounter;
-            if (*debounceCounter) {
-                --(*debounceCounter);
-            }
-        }
-    }
-
-    PIT_ClearStatusFlags(PIT, PIT_KEY_DEBOUNCER_CHANNEL, PIT_TFLG_TIF_MASK);
-}
-
-void InitKeyDebouncer(void)
-{
-    pit_config_t pitConfig;
-    PIT_GetDefaultConfig(&pitConfig);
-    PIT_Init(PIT, &pitConfig);
-    PIT_SetTimerPeriod(PIT, PIT_KEY_DEBOUNCER_CHANNEL, MSEC_TO_COUNT(KEY_DEBOUNCER_INTERVAL_MSEC, PIT_SOURCE_CLOCK));
-    PIT_EnableInterrupts(PIT, PIT_KEY_DEBOUNCER_CHANNEL, kPIT_TimerInterruptEnable);
-    EnableIRQ(PIT_KEY_DEBOUNCER_IRQ_ID);
-    PIT_StartTimer(PIT, PIT_KEY_DEBOUNCER_CHANNEL);
-}
diff --git a/right/src/key_debouncer.h b/right/src/key_debouncer.h
deleted file mode 100644
index c6455bc..0000000
--- a/right/src/key_debouncer.h
+++ /dev/null
@@ -1,18 +0,0 @@
-#ifndef __KEY_DEBOUNCER_H__
-#define __KEY_DEBOUNCER_H__
-
-// Includes:
-
-    #include "peripherals/pit.h"
-    #include "fsl_common.h"
-
-// Macros:
-
-    #define KEY_DEBOUNCER_INTERVAL_MSEC 1
-    #define KEY_DEBOUNCER_TIMEOUT_MSEC 100
-
-// Functions:
-
-    void InitKeyDebouncer(void);
-
-#endif
diff --git a/right/src/key_states.h b/right/src/key_states.h
index 9f48304..66eb9b9 100644
--- a/right/src/key_states.h
+++ b/right/src/key_states.h
@@ -10,10 +10,11 @@
 // Typedefs:
 
     typedef struct {
-        uint8_t debounceCounter;
+        uint8_t timestamp;
         bool previous : 1;
         bool current : 1;
         bool suppressed : 1;
+        bool debouncing : 1;
     } key_state_t;
 
 // Variables:
diff --git a/right/src/peripherals/pit.h b/right/src/peripherals/pit.h
index 530c805..0b22720 100644
--- a/right/src/peripherals/pit.h
+++ b/right/src/peripherals/pit.h
@@ -21,8 +21,4 @@
     #define PIT_KEY_SCANNER_IRQ_ID    PIT2_IRQn
     #define PIT_KEY_SCANNER_CHANNEL   kPIT_Chnl_2
 
-    #define PIT_KEY_DEBOUNCER_HANDLER PIT3_IRQHandler
-    #define PIT_KEY_DEBOUNCER_IRQ_ID  PIT3_IRQn
-    #define PIT_KEY_DEBOUNCER_CHANNEL kPIT_Chnl_3
-
 #endif
diff --git a/right/src/usb_report_updater.c b/right/src/usb_report_updater.c
index 7f52abe..d2f1c1d 100644
--- a/right/src/usb_report_updater.c
+++ b/right/src/usb_report_updater.c
@@ -13,7 +13,6 @@
 #include "layer.h"
 #include "usb_report_updater.h"
 #include "timer.h"
-#include "key_debouncer.h"
 #include "config_parser/parse_keymap.h"
 #include "usb_commands/usb_command_get_debug_buffer.h"
 #include "arduino_hid/ConsumerAPI.h"
@@ -350,10 +349,15 @@ static void updateActiveUsbReports(void)
             key_state_t *keyState = &KeyStates[slotId][keyId];
             key_action_t *action = &CurrentKeymap[activeLayer][slotId][keyId];
 
-            if (keyState->debounceCounter) {
-                keyState->current = keyState->previous;
+            if (keyState->debouncing) {
+                if ((uint8_t)(Timer_GetCurrentTime() - keyState->timestamp) > KEY_BOUNCE_TIME_MSEC) {
+                    keyState->debouncing = false;
+                } else {
+                    keyState->current = keyState->previous;
+                }
             } else if (!keyState->previous && keyState->current) {
-                keyState->debounceCounter = KEY_DEBOUNCER_TIMEOUT_MSEC + 1;
+                keyState->timestamp = Timer_GetCurrentTime();
+                keyState->debouncing = true;
             }
 
             if (keyState->current) {
diff --git a/shared/key_matrix.h b/shared/key_matrix.h
index e58e12c..abe221b 100644
--- a/shared/key_matrix.h
+++ b/shared/key_matrix.h
@@ -9,6 +9,7 @@
 // Macros:
 
     #define MAX_KEYS_IN_MATRIX 100
+    #define KEY_BOUNCE_TIME_MSEC 100
 
 // Typedefs: